Rotating joint

ABSTRACT

A rotating joint for connecting a fixed pipe to a rotating pipe and for providing a fluid seal for fluid flowing through the joint, wherein the joint has a pair of spaced seals which are subjected to fluid pressure acting in the joint in opposite directions to substantially equalize the thrust on the joint by the fluid flowing therethrough.

United States Patent Slator et al.

[ 1 Sept. 26, 1972 [54] ROTATING JOINT 2,394,800 2/1946 Murphy ..285/94[72] Inventors: Damon T. Slat0r; Albert L. Burns, g Jr. both of Houston,Tex 1 y 73 Assigneez Bowen Tools, Inc. FOREIGN PATENTS OR APPLICATIONSOct. Great Britain [21] Appl. No.: 84,415 Primary Examiner-Thomas F.Callaghan Att0rney-Pravel, Wilson & Matthews [52] U.S. Cl ..285/94,285/190 57 AB T [5l] Int. Cl ..Fl6l 27/00 l STRAC [58] Field of Search..285/190, 94, 134 A rotating joint for connecting a fixed P p to arotating pipe and for providing a fluid seal for fluid flowing [56]References Cited through the joint, wherein the joint has a pair ofspaced seals which are subjected to fluid pressure act- UNITED STATESPATENTS ing in the joint in opposite directions to substantially 836,98911/1906 Oliver ..285/190 fg f f fi i the pm by the flwmg 2,635,9314/1953 May ..285/190 X 2,8l0,59 2 l0/l957 Williams ..285/94 X 6 Claims,2 Drawing Figures /6 J! A J2 w 3/ 4/ 16 1 m4 22 /a 3/; I 20 26 s J, //0i 49 5/ 7 m 4 4 Md m I 264 J-l an 4b [g #5:: /0? 5 1; z: :66 m M6 0.6 7/

J! ma 3 //0 ROTATING JOINT BACKGROUND OF THE INVENTION 'have beengenerally unsatisfactory and even unusable at higher fluid pressure dueto binding between the parts caused by the great thrust loads at thehigher fluid pressures.

SUMMARY OF THE INVENTION The present invention relates to a rotatingjoint for establishing a sealed connection between a pair of pipes, oneof which is rotatable relative to the other, which joint has spacedseals with means for introducing the fluid between the seals to equalizethe pressure thrust acting on the joint, whereby frictional binding, andthrust forces tending to cause same, are minimized so that the joint issatisfactory for use at high fluid pressures.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevation of the rotatingjoint of this invention, shown mounted upon a typical reel for thewinding and unwinding of flexible hose or pipe thereon; and

FIG. 2 is an enlarged vertical sectional view of the rotating joint ofthis invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, the letter Adesignates generally the rotating joint ofthis invention, which ispreferably used with and mounted on, a rotatable reel R of anyconventional construction, upon which is wound a hose or pipe P in theknow manner. Briefly, the rotating joint A includes a mandrel which issecured to a rotatable shaft 12 of the reel R so that the mandrel 10rotates with the shaft 12. The shaft 12 has a pipe 14 therewith,preferably disposed internally of the drum 15 of the reel R and whichconnects with the hose or pipe P. A fixed inlet pipe 16 is connected toa sleeve 20 which is mounted on the mandrel 10 for relative rotationwith respect thereto, so that water or other fluid may be introducedfrom the fixed pipe or tube 16 through the rotating joint A to therotating pipe 14 for thus supplying the fluid to the hose or pipe P asthe reel R is being rotated for either winding or unwinding the hose orpipe P with respect to the reel R.

Considering the invention more in detail, the mandrel 10 has a flange10a at one end thereof which is adapted to engage a flange 12a on theshaft 12 to facilitate the attachment of the mandrel 10 to the shaft 12by means of studs 11, and nuts 11a, or any other suitable attachingmeans. Preferably the shaft 12 is provided with an end recess 12b forreceiving a projection 10b on the mandrel 10, having an O-ring 21therebetween for providing a fluid seal between the shaft 12 and themandrel 10.

The shaft 12 has a longitudinal passage 12c therein which is incommunication with a longitudinal bore 10c in the mandrel l0, and whichextends for at least a part of the length thereof. The passage 12c isalso in communication with the pipe 14 (FIG. 2).

In the preferred form of the invention, the longitudinal bore extendsfor approximately one half of the length of the mandrel l0 and is incommunication with one or more radial ports 10d which are joined by anannular recess Me at the outer peripheral surface of the mandrel 10.Normally, the annular recess 10e and the radial or lateral port 10d aredisposed at an intermediate portion of the mandrel 10, preferably atabout the mid-point thereof, and the bore 10c terminates outwardly ofsuch ports 10d (FIG. 2).

The mandrel 10 thus provides an extension of the shaft 12 externally ofthe reel R, with the shaft 12 being mounted in suitable conventionalbearings 22.

For introducing fluid, such as nitrogen gas, from the fixed pipe 16 intothe rotating joint A, the sleeve 20 is provided with a radial or lateralport 20a which is adapted to receive the threads 16a. The lateral port20a is in communication with an annular recess or groove 20b which isdisposed around the annular recess l0e. Only one of such annularrecesses Ne and 2b is required, so long as one of such annular recessesis in communication with a lateral port or ports in the other member.

The fixed pipe 16 and the lateral port 20a in which it is mounted isdisposed at an intermediate location on the sleeve 20 with respect to apair of longitudinally spaced seal means S and 5-1. The seal means S and8-1 have been deliberately illustrated in two forms, although it shouldbe understood that the seal means S and 8-1 may be identical. The sealmeans S includes a plurality of resilient seal rings 25 formed of rubberor other similar material and which have rigid rings 26 on each sidethereof, formed of steel or similar material. The outermost ring 26 hasone or more lateral slots 26a at the right hand end thereof (FIG. 2) forthe passage of grease to the inner surfaces of the rings 25 and 26, aswill be more evident hereinafter. Preferably the adjacent surfaces 25aand 26b of the rings 25 and 26, respectively, are spaced apart so thatthe inner annular edges or surfaces of the resilient rings 25 are urgedinto sealing engagement with the external surface of the mandrel 10 bythe fluid pressure exerted thereon from the gas flowing through therotating joint A.

The seal means S-l, although similar to the seal means S, differs incertain respects as shown in FIG. 2 and as explained hereinafter. Theseal means 8-1 includes a plurality of resilient seal rings made ofrubber or similar material which are mounted with a plurality of rigidrings 126 formed of steel or other similar'material. The outermost ring126 has one or more lateral passages 126a through which grease may passto the seal means 8-1, as will be more evident hereinafter. An O-ring126b is provided on the intermost ring 126 to seal between the exteriorof the seal S-1, and the sleeve 20.

Bushings 30, preferably madeof bronze, are disposed at each end of thesleeve 20 and each is surrounded by a retaining head 31 which serves toforce the bushing 30 towards the respective seal means S or S-l forcompressing the outer portion of each of the resilient rings 25 and 125,respectively. The adjacent surfaces 125a and 126b on the adjacent rings125 and 126, respectively, are spaced apart to facilitate the annularlip seal by the inner portion of each of the resilient rings 125 withthe external surface of the mandrel 10. The space thus provided iscloser to the port a than the opposite sides of the rings 125, with theresult that sealing takes place with each of the seal rings 125successively so that until substantial wear occurs on the first seal(the seal on the right in FIG. 2), such first seal is the only sealwhich is effective. Because of the successive sealing action of the sealrings 125, as compared to the substantially uniform sealing action bythe seal rings 25, the life of the seal means 8-1 is longer than that ofthe seal means S, assuming the same operating conditions and otherfactors.

Grease is introduced into each of the seal means S and S-l throughgrease fittings 32, each of which communicates with its respective sealmeans. The grease fittings 32 are conventional pressure fittings whichpermit the introduction of grease therethrough, but which prevent theescape of grease therefrom. Thus, grease is introduced to the seal Sthrough the fitting 32 associated therewith so that the grease passesthrough the opening or notch 26a and fills all of the spaces within theseal means S and then flows to an annular space 27 in which a floatingseal ring 28 which is formed of rubber or similar material is disposed.The seal ring 28 is forced to the left as viewed in FIG. 2 so that thespace 27 is filled with the grease. So that there will not be an airlock when filling the seal means S and the spaces therewith with thegrease, a grease fitting or plug 34 which is mounted on the sleeve 20 isremoved so that the grease may exit through a passage 206, indicating tothe operator that all of the spaces have been filled with grease. Thefitting 34 may then be resecured as illustrated in FIG. 2 to retain thegrease within the sleeve 20. The combination of the grease and theresilient rubber seal rings is significant in the present inventionbecause the fluid which normally passes through the rotating joint is adry gas which has no lubricating properties as such and therefore, thegrease lubricates the seal rings 25 which minimizes friction between themandrel 10 and the seal rings 25 to thereby reduce heat and wear andlengthen the life of the seal S. The same is true with respect to theseal rings 125 in the seal S-l.

A space 27 and a floating seal ring 28"which are similar to the space 27and the floating ring 28, respectively, are employed in conjunction withthe seal means S-l. Also, a grease fitting or plug 34' is provided in apassage 20d in the sleeve 20 so that grease may be introduced throughthe left hand grease fitting 32 (as viewed in FIG. 2), and then into theseal means 8-1 to fill-all of the spaces therewith, including the space27' and the passage 20d. The fitting 34' is removed during the fillingof the spaces with respect to the seal means 8-1 with grease, and it isthereafter repositioned as shown in FIG. 2 for providing the closed areafor such grease.

The annular space 27 and 27' are each of sufficient size to provide areservoir of grease between the floating rings 28, 28 and the seals S,8-1, respectively, to compensate for grease loss through the sealingmeans S and 8-1 in normal extended operation. Each of the floating rings28, 28 is free to move axially and fits closely in the annular spaces27, 27', respectively, between the mandrel 10 and the sleeve 20, thus,the hydrostatic pressure on the grease in the annular spaces 27, 27 isat all times essentially equal to the pressure of the fluid beingcirculated through the rotating joint A.

In the event of gradual loss of grease through the sealing means S or8-1, or both, its respective floating ring 28 or 28 will automaticallymove to compensate for such loss of grease, thus effectively isolatingthe sealing means from the fluid being circulated until the supply ofgrease in each reservoir 27, 27' is exhausted. The supply of grease canbe replenished even while the rotating joint is in operation, by pumpinggrease in through the respective fittings 34, 34' at a pressure higherthan the working pressure of the fluid being circulated, displacing thefloating rings 28, 28', and refilling the annular spaces 27, 27'.

Although the heads 31 are preferably threaded at 31a to the sleeve 20,they may be attached to the sleeve 20 with any other suitable means.Additional fluid seals such as O-rings 40, 41, 42 and 43 are alsoprovided with the heads 31 to assure that leakage is prevented inproximity to the heads 31.

The sleeve 20 and the parts therewith are removable from the mandrel 10by sliding same axially to the left as viewed in FIG. 2, but a retainingplug 45 is preferably mounted on the outer end of the mandrel 10 bymeans of a cap screw 46 so as to normally prevent any removal of thesleeve 20 from the mandrel 10. However, upon a removal of the cap screw46 and the retaining plug 45, it will be appreciated that the entiresleeve 20 with its seals S and 8-1 and heads 31 may be removed for thereplacement or repair and for such other servicing as may be required.

In the operation or use of the rotating joint A of this invention, thejoint is attached to the end of a rotating shaft such as the shaft 12,and it is also connected with a fixed pipe 16. Normally, gas such asnitrogen is introduced from a suitable source (not shown) through thepipe 16 and then through the lateral passage 20a, the annular recess20b, the annular recess l0e, and one or more lateral passages 10d to thebore of the mandrel 10. The bore 10c is in communication with thepassage in the shaft 12 so that the gas thus flows to the interior of arotatable pipe 14 which rotates with the shaft 12 on the reel R.

Since the gas pressure is thus introduced into the rotating joint Abetween the pair of longitudinally spaced, equal area, seal means S and8-1, the force exerted by the fluid on the joint A, and particularly thesleeve 20 is equalized in both longitudinal directions so that there issubstantially no binding or thrust force on the sleeve 20. Therefore,the frictional resistance to the relative rotation between the mandrel10 and the sleeve 20 is minimized and is due essentially only to thefrictional contact between the resilient rings 25 and and also thefloating seal rings 28 and 28'. However, since there is grease fillingthe spaces with respect to the seal means S and S-1, as previouslyexplained, such frictional resistance is again minimized. The greasealso facilitates the anti-friction support provided by the bushings 30at each end of the sleeve 20. Although thrust rings 50 and 51 areprovided on the rotating joint A, they are normally of little value andcould be omitted since the fluid forces acting in the longitudinaldirections are equalized, or are substantially equalized. Thus, anylongitudinal or axial force exerted on the sleeve 20 which would causesome movement of the sleeve 20 relative to the mandrel in a longitudinalor axial direction, would be relatively small and would not create anysubstantial binding of the parts of the joint, as compared to the priorart wherein substantially all of the thrust is in one longitudinaldirection between the rotating parts.

The foregoing disclosure and description of the invention areillustrative and explanatory thereof, and various changes in the size,shape, and materials as well as in the details of the illustratedconstruction may be made without departing from the spirit of theinvention.

We claim:

1. A rotating joint for connecting together a pair of pipes, one ofwhich is rotatable relative to the other, for flowing fluid under highpressure therethrough, comprising:

a mandrel having a longitudinal bore extending for at least part of thelength thereof and lateral port means at an intermediate portion of themandrel;

a sleeve surrounding said mandrel;

means mounting said sleeve on said mandrel for relative rotationtherebetween;

longitudinally spaced annular lip-type seal means between said mandreland said sleeve;

said sleeve having a fluid passage disposed between said seal means andcommunicating with said lateral port means to thereby establish fluidflow through the rotating joint with the pressure thereof actingsubstantially equally in opposite longitudinal directions a floatingseal ring disposed on each side of said fluid passage in said sleevebetween said sleeve and said mandrel, and each being locatedlongitudinally between said fluid passage and one of said seal means;

each of said seal rings being spaced longitudinally inwardly from theseal means therewith for providing an annular space which may also befilled with grease; and

said sleeve having a grease injection passage for each of said sealmeans located longitudinally outwardly thereof on the opposite side ofsaid seal means from said annular space and said floating seal ringwhereby grease may be injected into each of said seal means and saidannular space for filling all spaces with said seal means and saidannular space.

2. The rotating joint set forth in claim 1, including:

means on one end of said mandrel for attaching same to a rotatable reelshaft for rotation therewith relative to said sleeve.

3. The rotating joint set forth in claim 1, including:

a bushing at each end of said sleeve disposed between said sleeve andsaid mandrel to minimize wear and facilitate relative rotation betweensaid mandrel and said sleeve.

4. The rotating joint set forth in claim 3, including:

a head on each end of said sleeve surrounding one of said bushings andadapted to retain same on said sleev ;and means or ad usting each headlongitudinally on said sleeve for providing an adjustable compressiveforce on each seal means.

5. The rotating joint set forth in claim 1, wherein each of said sealmeans includes:

a plurality of resilient seal rings, each of which has inner and outerannular lip surfaces in contact with said sleeve and said mandrel;

a plurality of rigid rings disposed between and on each side of saidresilient rings; and

means on each end of said sleeve adjustable longitudinally for confiningsaid resilient rings and said rigid rings as an assembly.

6. The rotating joint set forth in claim 5, wherein:

adjacent annular surfaces on said rigid rings and resilient rings arespaced from each other, with the spaces being longitudinally disposed onthe side of each resilient ring which is closer to said fluid passage sothat pressure acting on each seal means acts on said resilient sealrings successively to minimize wear thereof and to prolong the overalllife of each said seal means.

1. A rotating joint for connecting together a pair of pipes, one ofwhich is rotatable relative to the other, for flowing fluid under highpressure therethrough, comprising: a mandrel having a longitudinal boreextending for at least part of the length thereof and lateral port meansat an intermediate portion of the mandrel; a sleeve surrounding saidmandrel; means mounting said sleeve on said mandrel for relativerotation therebetween; longitudinally spaCed annular lip-type seal meansbetween said mandrel and said sleeve; said sleeve having a fluid passagedisposed between said seal means and communicating with said lateralport means to thereby establish fluid flow through the rotating jointwith the pressure thereof acting substantially equally in oppositelongitudinal directions a floating seal ring disposed on each side ofsaid fluid passage in said sleeve between said sleeve and said mandrel,and each being located longitudinally between said fluid passage and oneof said seal means; each of said seal rings being spaced longitudinallyinwardly from the seal means therewith for providing an annular spacewhich may also be filled with grease; and said sleeve having a greaseinjection passage for each of said seal means located longitudinallyoutwardly thereof on the opposite side of said seal means from saidannular space and said floating seal ring whereby grease may be injectedinto each of said seal means and said annular space for filling allspaces with said seal means and said annular space.
 2. The rotatingjoint set forth in claim 1, including: means on one end of said mandrelfor attaching same to a rotatable reel shaft for rotation therewithrelative to said sleeve.
 3. The rotating joint set forth in claim 1,including: a bushing at each end of said sleeve disposed between saidsleeve and said mandrel to minimize wear and facilitate relativerotation between said mandrel and said sleeve.
 4. The rotating joint setforth in claim 3, including: a head on each end of said sleevesurrounding one of said bushings and adapted to retain same on saidsleeve; and means for adjusting each head longitudinally on said sleevefor providing an adjustable compressive force on each seal means.
 5. Therotating joint set forth in claim 1, wherein each of said seal meansincludes: a plurality of resilient seal rings, each of which has innerand outer annular lip surfaces in contact with said sleeve and saidmandrel; a plurality of rigid rings disposed between and on each side ofsaid resilient rings; and means on each end of said sleeve adjustablelongitudinally for confining said resilient rings and said rigid ringsas an assembly.
 6. The rotating joint set forth in claim 5, wherein:adjacent annular surfaces on said rigid rings and resilient rings arespaced from each other, with the spaces being longitudinally disposed onthe side of each resilient ring which is closer to said fluid passage sothat pressure acting on each seal means acts on said resilient sealrings successively to minimize wear thereof and to prolong the overalllife of each said seal means.